Electronic device and surge handling

ABSTRACT

The present invention provides for an electronic isolator, or barrier, device arranged for receiving field wiring from a field element and further including connection means arranged to receive a surge element for providing surge functionality to the device, and to provide surge protection to the connectivity by way of the field wiring, the device arranged such that the surge element connects to the device and to the said field wiring by way of the said connection means so that operational connection/disconnection of the surge element to the device does not require disconnection of the field wiring from the device.

Various forms of electronic device find a wide variety of use in avariety of process industries. In particular, field elements such assensors and actuators are commonly deployed in field locations within aprocess environment which, in some instances, can be required to offerappropriate degrees of safety such as explosion-proof characteristicsand characteristics of so-called intrinsic safety.

In view of the nature of such deployment, the reliable and safeoperation of such field elements is paramount and surge devices arecommonly employed as part of the connectivity to the field elements.

Any such surge functionality commonly requires surge protection inparticular in relation to connections from the field elements.

Surge devices have commonly been employed so as to provide for suchreliable surge-protection functionality.

Electronic devices such as, but not limited to, known field elementscommonly connect to appropriate process circuitry relevant to thespecific process environment by way of a functional cabinet in whichsome appropriate electrical functionality, such as zener barrier,isolation, remote I/O or other functionality is provided. Input/outputwiring then provides for the appropriate connection to the appropriateprocess circuitry.

When a plurality of electronic devices are provided in a particularenvironment, such as a plurality of field elements within a particularprocess environment, it becomes necessary to make appropriateconnections from the field elements to appropriate zener barrier,isolation or other functionality within the function cabinet so thatongoing connections are made to the correct input/output lines leadingto the process circuitry.

Routine surge protection functionality for such connections from, forexample, field elements, is commonly provided by a separate surgecabinet comprising a plurality of surge elements for connection betweenthe field elements and process circuitry by way of the functional (e.g.zener barrier/isolator) cabinet.

The surge cabinet can be arranged for connection from the field elementsby way of an extra marshalling cabinet, generally arranged withmarshalling exchange wiring serving to configure the requiredconnectivity of each of the field elements.

When using isolators in particular, it is often necessary to fit surgeelements on the outside lines and as noted this can require anadditional cabinet and associated additional costs. Space is alsorequired for the additional cabinet within the cabinet room andextensive wiring requirements arise in the cabinet itself requiringcareful labour input and cross checking at the time of commissioning ofthe system and during subsequent fault detection and testing.

A known alternative is to employ a bulky surge module that can beplugging into an isolator device, but this also requires that the fieldwiring must be disconnected from the isolator and re-connected onto thesurge module which of course can prove disruptive, inefficient andinconvenient and can lead to operational problems due to the possibilityof incomplete, or incorrect, re-connection.

The potential for the retro-fitting of surges can therefore be limitedand it can often be the case that there is no suitable location withinthe cabinet room for such retro fitting and the required extensiverewiring to achieve such retro fitting can lead to lengthy downtime atthe process plant. There is also a likelihood of errors arising in therewiring connectivity which cannot be ignored or excluded withcertainty. Also, the deployment of surge elements in such known mannertherefore remains an incentive to employ an additional cabinet with theassociated disadvantages noted above.

The present invention seeks to provide for the surge-handlingarrangement having advantages over known such arrangements and, inparticular, allowing for ready retro fitting in a more simplified, butreliable manner than currently known.

According to a first aspect of the present invention there is providedan electronic isolator device arranged for receiving field wiring from afield element and further including connection means arranged to receivea surge element for providing surge functionality to the device, and toprovide surge protection to the connectivity by way of the field wiring,the device arranged such that the surge element connects to the deviceand to the said field wiring by way of the said connection means

The invention proves advantageous insofar as it is unnecessary todisconnect the field wiring from the isolator device in order to fit thesurge element and so the principal problems of the known are can bereadily avoided. Further it is found that there is no need to provideany additional wiring for the surge element or indeed an additionalrelated housing such as a surge cabinet. The potential for wiring errorsthat can arise in the current art can therefore be eliminated since itis an inherent feature of the invention that each surge element isclearly associated with the isolator device.

Advantageously, the surge element can therefore be arranged to beremovably mounted to the isolator device in a manner requiring nointerference with the connection of the device to the field wiring.

In one example, the said connection means is arranged for parallelconnection of the surge means with respect to the field wiring. Further,the said connection means can be arranged to connect to the surge deviceto the field wiring from within the device.

It should be appreciated that the device can comprise an intrinsicallysafe isolator.

According to another aspect, the present invention can provide for anelectronic barrier device arranged for receiving field wiring from afield element and further including connection means arranged to receivea surge element for providing surge functionality to the device, and toprovide surge protection to the connectivity by way of the field wiring,the device arranged such that the surge element connects to the deviceand to the said field wiring by way of the said connection means.

Advantageously, the surge element is arranged to be located at the pointof connection of input/output lines to the device. In particular, thesaid input/output lines in this arrangement comprise field elementlines.

It should therefore be appreciated that the electronic functional devicecan comprise any one or more of, or combination of, a zener barrierdevice and isolator device

In one particular embodiment, the surge element is arranged to beconnected to the device by way of any appropriate means such aspress-fit means, male/female engagement means and/or screw thread means.

The invention can also provide for a plurality of surge elementsassociated with a respective plurality of isolator or barrier devices.In this manner, the plurality of devices and their associated surgeelements, whether pluggable or not, can be provided as part of theelectronic functional device cabinet.

The invention is described further hereinafter, by way of example only,with reference to the accompanying drawings in which:

FIG. 1A is a schematic representation of a known isolator systememploying surge-handling functionality;

FIG. 1B comprises a more detailed view of parts of the cabinets of thesystem of FIG. 1A;

FIG. 2A comprises a schematic block diagram of an isolator cabinetaccording to an embodiment of the present invention;

FIG. 2B comprises a detailed view of part of the cabinet of FIG. 2A,with the resultant suppression of one cabinet;

FIGS. 3A-3E comprise a series of illustrations of the connection of asurge element to an isolator device as known in the art; and

FIGS. 4A-4C comprise a series of illustrations of the pluggableconnection according to an embodiment of the present invention.

Turning first to FIG. 1A, there is illustrated an electronic functionalcabinet such as an isolator cabinet 1 having isolator elements 4connected to surge elements 5 located within a surge cabinet 2.

Input/output wiring lines 10 lead from the isolator cabinet 1 to processelectronics (not shown) and the connectivity between the isolatorcabinet 1 and the surge cabinet 2 is achieved by way of isolator-surgewiring lines 11.

In the illustrated example, onward connection from the surge cabinet 2is to a plurality of field elements (not shown) by means of surge-fieldelement wiring lines 12. As a further variant but not illustrated inFIG. 1A, the output wiring 12 from the surge cabinet 2 can lead to anadditional cabinet, such as a marshalling cabinet to assist with theappropriate configuration of connectivity of the plurality of fieldelements. Examples of the basic component elements of each surge element5 are illustrated in this schematic representation of FIG. 1A.

FIG. 1B provides further illustrative detail within each of the isolatorcabinet 1 and surge cabinet 2. As can be seen, a plural series ofisolator devices 4 are mounted within the isolator cabinet 1 and eachconnects at input/output sides to the input/output wiring 10 andisolator-surge wiring 11. A corresponding series of surge devices 5 arelikewise mounted within the surge cabinet 2, with a separate surgeelement being provided in relation to each of the isolator-surge lines11, and each of the surge-field element lines 12.

As clearly illustrated in FIGS. 1A and 1B, the provision of the surgefunctionality requires the additional cabinet 2 which leads toadditional cost and also disadvantageously requires additional spacewithin the cabinet room and leads to additional wiring overheads. Theadditional cabinet also comprises part of a series connection that mustbe broken if it is required to change and/or install the surge element,and which disadvantageously results downtime.

Such disadvantageous disconnection etc. also arises in relation to theprior art such as that discussed further below with reference to FIGS.3A-3E and in which connections must be broken to retrofit the surgeelement and in a scenario in which an extra cabinet is not required,assuming of course that such relatively large add-ons can fit within theisolator cabinet.

Turning now to FIG. 2A, there is provided a schematic representation ofan isolator cabinet 101 according to an embodiment of the presentinvention.

The isolator cabinet 101 in this example includes isolator functionality104 connecting, by means of input/output wire lines 110, to processcircuitry, and by way of output wire lines 112, to a plurality of fieldelements. Again such connection to the field elements can be by way of amarshalling cabinet if required.

Also schematically illustrated with reference to FIG. 2A is theprovision of one surge element 105 of a possible plurality of pluggablesurge elements 105 for providing surge protection from the input/outputfield line 112 illustrated in FIG. 2A as required. The basic electronicfunctionality within the pluggable surge element is illustratedschematically in FIG. 2A. As can be appreciated, the presence of thepluggable surge element (105) does not require the removal/reconnectionof the field lines 112.

Turning to FIG. 2B, further detail of the configuration of the surgedevices 104 within the surge cabinet 101 is illustrated and where eachof the pluggable surge elements 105 is illustrated in relation to theisolator elements 104 requiring surge protection.

As noted, each of the isolator elements 104 is provided with anappropriate socket arrangement 115 via which the surge element 105 canbe removably plugged into the isolator element 104 as required andelectrically connected to the input/output field lines 112 so as toprovide for the required surge functionality. Again, and importantly,the operative connection of the surge element to, and disconnectionfrom, the isolator is achieved without requiring any disconnection ofthe field wiring. This therefore allows for “live”connection/disconnection of the surge element with no, or minimal, needfor “downtime”.

The advantageous avoidance of a separate surge cabinet can therefore beachieved but without the limitations of the prior art.

The isolator devices 104 are therefore advantageously arranged to acceptthe pluggable surge elements 105 within their own cabinet 101, and suchdevices can readily connect exactly where needed in relation to theinput/output field lines 112.

Further, the surge element 105 can be plugged-in or removed while aprocess is running and such configuration provides immediate indicationas to which of the input/output field lines 112 is associated with asurge device. The simple plugability also avoids the need foradditional, fault prone, wiring, in addition to avoiding the need forthe separate surge cabinet as noted above. Yet further, retro-fitting ofsuch pluggable surge elements/modules 105 can also readily be achievedas required.

Referring now to FIGS. 3A-3E there is shown, in series format, themanner of connection of a surge element to an isolator device and asknown in the current art.

Referring first to FIG. 3A, there is illustrated input/output lines 110connecting to an isolator device 204 which connects in turn to outputwire lines 112 in this example comprising field wiring 112. In order toachieve the introduction of surge functionality according to this knownart, it is necessary that the field wiring 112 be disconnected from theisolator device 204 as illustrated in FIG. 3B so as to allow for theinsertion, in serial fashion, between the isolator device 204 and thefield wiring 112, a surge element module 205 and as illustrated withreference to FIG. 3C.

FIG. 3D shows the next stage in the procedure in which the surge element205 is first connected to the isolator device 204 and then, asillustrated in FIG. 3E, the field wiring 112 is then connected in turnto the surge element 205. Accordingly, the previously disconnected fieldwiring 112 no longer makes direct connection to the isolator device 204,but rather now connects to the surge element 205 serving as anintermediate element between the field wiring 112 and the isolatordevice 204.

As will be appreciated, such operational fitting of the surge element205 has required the disconnection, and subsequent reconnection, of thefield wiring 112 which exhibits a wide variety of disadvantages butleast of which comprise disruption and downtime to the operation of thesystem employing the wiring and isolator device, but also opens thepotential for further disruption if such disconnection cannot bereversed in a relatively simple and efficient manner.

Turning now to an example of the present invention as illustrated withreference to FIGS. 4A-4C particular advantage of the present inventionwill be readily apparent.

Turning first to FIG. 4A, an isolator device 104 according to anembodiment of the present invention is connected to input/output wirelines 110 and field lines 112 as with the prior art configuration.However, as an important difference, the isolator 104 includesconnection means 115 allowing for the connective plugability of a surgedevice 105 directly into the isolator 104 and without requiring anydisruption to the connection of the isolator device 104 to the fieldwiring 112.

This advantageous feature of the present invention is illustratedfurther with reference to FIG. 4B illustrating a suitable surge device105 arranged for insertion into the connector arrangement 115 of theisolator device 104. As will then be appreciated, such connection isquite independent of the nature of the connection between the isolator104 and the field lines 112.

FIG. 4C completes the illustration of the connection process andillustrates the surge element 105 plugged into the connector 115 of theisolator device 104 so as to effectively achieve parallel connectionwithin the isolator device 104 and with respect to the field wiring 112for operative connection thereto.

As will be readily appreciated, the surge can be plugged/unplugged, i.e.connected/disconnected as many times as appropriate and, on eachoccasion, there is no effect on the manner of connection between theisolator device 104 and the field wiring 112 and thus very little, ifany, disadvantageous effect on the operation of the system employing theisolator device 104 since “live plugability” can be achieved between thesurge element 105 and the isolator device 104 without requiring anydowntime.

The present invention therefore provides for a particularly advantageousand simplified manner of connection of a surge element to an operationaldevice such as an isolator device and which further enhances manner inwhich such surge functionality can be provided without requiring aseparate surge cabinet.

Of course, it will be appreciated that the present invention is notrestricted to the details of the foregoing embodiments. In particular,it is envisaged that the invention be provided in relation to any formof isolator, with offering intrinsic safety or otherwise, or indeed anyform of barrier device, such as a zener barrier device.

While the above mentioned embodiment of the invention is discussed inrelation to an electronic functional device, and device cabinet, in theform of an isolator device and cabinet, it should be appreciated thatthe invention can be readily provided in relation to zener barrierdevices and zener barrier cabinets or indeed a combination thereof.

The invention therefore is not restricted to the details of the forgoingembodiments particularly as regards the nature ofconnection/disconnection of each of neither the surge elements 105 northeir component parts.

1. An electronic isolator device arranged for receiving field wiringfrom a field element, the electronic isolator device comprising: aconnector configured to receive a surge element for providing surgefunctionality to the electronic isolator device, and to provide surgeprotection to the connectivity by way of the field wiring, the connectorconfigured to connect the surge element to the electronic isolatordevice and to the field wiring.
 2. The electronic isolator device asclaimed in claim 1, wherein the connector is arranged for parallelconnection of the surge element with respect to the field wiring.
 3. Theelectronic isolator device as claimed in claim 1, wherein the connectorconnects the surge element to the field wiring from within the device.4. The electronic isolator device as claimed in claim 1, furthercomprising an intrinsically safe isolator.
 5. An electronic barrierdevice arranged for receiving field wiring from a field element, theelectronic barrier device comprising: a connector configured to receivea surge element for providing surge functionality to the electronicbarrier device, and to provide surge protection to the connectivity byway of the field wiring, the connector configured to connect the surgeelement to the electronic barrier device and to the field wiring.
 6. Theelectronic barrier device as claimed in claim 5 further comprising azener barrier device.
 7. The electronic barrier device as claimed inclaim 5, wherein the connector is configured to provide visualindication of the electronic barrier device protected by the surgeelement when the surge element is received by the electronic barrierdevice.
 8. The electronic barrier device as claimed claim 5, wherein theconnector is configured to connect to the surge element by way of apress-fit connection.
 9. The electronic barrier device as claimed inclaim 5, wherein the connector is configured to connect to the surgeelement by way of a male/female connection arrangement.
 10. Theelectronic barrier device as claimed in claim 5, wherein the connectoris configured to connect to the surge element by way of a threadedconnection.
 11. The electronic barrier device as claimed in claim 5,wherein the connector is configured to locate the surge element at thepoint of connection of the electronic barrier device to field wiring.12. The electronic barrier device as claimed in claim 5 in combinationwith one or more additional electronic barrier devices to form anelectronic system element.
 13. The electronic barrier device as claimedin claim 5 in combination with an electronic functional device cabinet.